Rotary magnetic actuator



April 26, 1960 A. J. BUCHTENKIRCH 2,934,680

ROTARY MAGNETIC. ACTUATOR Original Filed Dec. 28, 1954 INVENTOR.

ARTHUR BUCHTENKIRCH Gm .5 W

ATTORNEYS United States Patent 2,934,680 ROTARY MAGNETIC "ACTUATOR Arthur J. Buchtenkirch, Glen Cove, N.Y., asslgnor to North Atlantic Industries, Inc., Westbury, N.Y.

2 Claims. (Cl. 317-197) This invention relates to a rotary magnetic actuator and is a division of my prior application, Ser. No. 478,059, tiled December 28, 1954, now Patent No. 2,872,628. I

The invention herein relates to an actuator formed of a cup shaped or cylindrically shaped magnetic structure having teeth formed on one end thereof and a similarly formed armature having teeth which mesh with the magnetic structure teeth wherein the teeth form the pole faces and armature faces.

An object of this invention is to form a rotary magnetic actuator which is inexpensive tomanufacture, and which is a closed self contained unit, and wherein a maximum degree of torque is obtained with a limited angular rotation.

These and other objects and advantages of this invention will become apparent upon reading the following description of which the attached drawings form a part.

With reference to the attached drawings, in which:

Fig. 1 is an elevational view of the rotary magnetic actuator.

Fig. 2 is a cross-sectional view of the device shown in Fig. 1.

Fig. 3 is a view taken in the direction of arrows 3-3 of Fig. 1 and shows the top of the magnetic structure.

Fig. 4 is an enlarged segment of the pole piece structure and shows the operation of the tooth shaped pole pieces and armature faces.

With reference to the attached drawings, the rotary magnetic actuator herein consists basically of four parts: A magnetic structure 11, an armature 12, a rotatable shaft 30, and an electrical coil 40.

The magnetic structure 11 is cup shaped or cylindrically shaped, having a thin wall 14 and a base 15 closing the bottom of the cylinder and which may be formed integral with the wall. The armature 12 is formed similarly to the magnetic structure in that it is also cup shaped or cylindrically shaped, with a thin side wall 18 and a base 19.

The magnetic structure is provided with a plurality of teeth 20 equally spaced around the open end of the magnetic structure. These teeth 20 form pole pieces, and with reference to Fig. 4, it can be seen-that they are spaced apart a predetermined distance which is shown by the spacing land 21. The teeth are provided with inclined faces 22 which form pole faces and which extend from the base of the tooth to the top of the tooth.

The armature is likewise provided with teeth 25 spaced apart by land 26 and having inclined armature faces 27 which slope approximately the same as the magnetic structure pole faces 22. The pole faces and the armature faces may be arranged with parallel slopes or the slopes may be arranged slightly non-parallel. The degree of slope and the relative arrangement of the two slopes determine, to a great extent, the amount of torque and the speed of reaction obtained by the rotation of the armature.

Ordinarily, the armature and the magnetic structure are arranged coaxially and are inverted relative to each other with their teeth meshed. The rotatable shaft 30 isalsoarranged coaxial with both the armature and the magnetic structure. The shaft extends through an opening 31 in the armaturebase plate 19 and is rigidly secured to the armature so that the armature and shaft rotate together. Also, the shaft is rotatably journaled in a sleeve 32 formed in the magnetic structure and extending upwards from the base plate 15 (see Fig. 2).

A suitable spring 35 is connected between the shaft 30 and the magnetic structure 11 so that after rotation of the shaft, the shaft will be returned by the spring to its original non-rotated position. Also, suitable support brackets 36 are arranged to rigidly connect the magnetic structure to some support so that it is non-rotatably held.

An electrical coil 40 is positioned within the magnetic structure to surround the sleeve 32 and the shaft 30 and to rest upon the base plate 15.

To reduce friction, it is desirable to provide a suitable bearing 44, such as a ball bearing or roller bearing between the base 19 of the armature and the top of the sleeve 32.

In operation, the coil is electrically. energized by an electrical source (not shown) to thus magnetize the magnetic structure and particularly the pole pieces or teeth 20. With the pole faces 22 each facing an armature face 27, the armature faces are attracted towards the pole faces as indicated by the force arrows showing the magnetic force 42. This attraction causes the armature 12 and the shaft 30 to rotate in the direction of arrow 43 (see Fig. 4). The rotation continues until the armature faces contact the pole faces.

When the electrical energy to the coil is disconnected, the magnetic force releases and the spring 35 returns the shaft and the armature to its original non-rotated position wherein the pole faces and the armature faces are spaced apart a maximum distance.

This invention may be further developed within the scope of the following attached claims. Accordingly, it is desired that the foregoing description be read as being merely illustrative of an operative embodiment of this invention and not in a strictly limiting sense.

I now claim:

1. A rotary magnetic actuator comprising a magnetic structure and an armature, each being formed of a tubular shaped, thin wall cylinder with their wall thicknesses and diameters being the same, and the two being axially aligned and arranged end to end; the facing ends of the cylinders being formed in a tooth shaped configuration with a plurality of teeth equally spaced apart around the circular ends of the cylinders and with each tooth having an inclined surface which slopes from the base of that respective tooth to its free end, and with the teeth on the armature cylinder corresponding in shape and size with the teeth on the magnetic structure cylinder to form inclined armature faces and with the teeth on the armature meshing with the teeth on the magnetic structure with the inclinedsurfaces of the corresponding teeth facing towards each other and with the inclined surfaces of magnetic structure teeth forming pole faces; means for supporting the armature cylinder for rotation about its axis and means non-rotatably supporting the magnetic structure cylinder; and an electrical coil arranged coaxially within the magnetic structure cylinder for magnetizing its pole faces wherein magnetic flux passes from the pole faces to their corresponding armature faces to attract the armature faces and cause the armature to rotate in a direction to reduce the air gaps between the opposing pole and armature faces, and with the flux being restricted in a direction radially of the cylinder axes to the thickness of the cylinder walls and the radial .area of. restriction of the flux being located a considerable distance from the cylinder axes.

2. A rotary magnetic actuator comprising a magnetic structure and tan. armature, each, being formed, asaxclosed bottom, :cylin'drically shaped cup -having:thin:side walls of the, same internal and external diameters, with the free, open ends of the side walls being shaped into. a plurality of teeth, said teeth beingspaced apart a predetermined distance and each tooth being formed by ,a section of and extending ;-in the direction of its respective wall, the teeth on the magnetic structure corresponding inshape and spacing to the teeth on thearmature; the armature being arrangedzcoaxially with and inverted relative to the magneticstructure wherein the teeth-of each are meshed together; each tooth havingan inclined surface extending from the base to the end of the'tooth to form inclined pole faces on the magnetic structure and V inclined armature faces on'the armature'witheach-of between the respective opposed armature faces and pole faces, the flux being restricted within a cylindrically shaped area corresponding to the area'of'and internal and external diameters of the free ends of the armature and magnetic structure free ends, with the cylindrical area within which'the flux may pass being spaced a considerable distance from the cup .axes, whereby the pole faces attract the armaturefaces and the armature rotates in response to such attraction.

References Cited in the file .of this patent UNITED STATES PATENTS 

